Method of making drills.



FUNITEB STATES PATENT LEWIS ameson, OF NEW BEDFORD, MASSACHUSETTS, ASSIGNOR To MORSE-TWIST Damn 1 amcnmn COMPANY, or NEW BEDFORD, MASSACHUSETTS, A CORPORATION or MASSA- OHUSETTS'.

Specification of Letters Paiterit.

.Mn'rnoD or MAKING nmLLs.

Patented Fania, 1908.

Application filed December 13' 1907- Serial No. 407|O31- i citizen of'the'United States, and a resident of New Bedford, in the county of Bristol and cation;

State of Massachuset'tafhave invented a new and useful Improvement inMethods of -M akg Drills, ofwhichthe following is a specifi- My invention relates to methods of making two-part drills, or drills of which the bit or boring portion and the shank or the portion. whereby the drill is held in the chuck for operation, are formed'separately and afterward united.

.The object of my invention, which is applicable chiefly to the manufacture Df tVOf part drills of the smallersizes, is to provide a method'whereby the bit and shank of a twopart drill may be firml united by a joint which will Withstand t e torsional strains arising from the use of the drill in practice,

and whereby in. the completed drill the bit will be accurately centered in. the shank and the sha e of the latter be maintainedtrue and undistorted.

A two-part drill may be manufactured by my-new and improved method much more conveniently and cheaply than by the methods now employed whereby the bit and shank are united by electric Welding or by usoldering or by means of a pin passing through the members, and in practice the drills made by my method have been found more expensive one-part drill.

Heretofore it has been attempted to make -two part drills by forming a shank with a long rounded extension .in which a hole was bored, the butt-end of the bit inserted in said .hole and the metal of the extension then compressednpon the bit by two pairs of rapidly rotating hammers provided with dieplates and cooperating pair-by-pair with saidfrounded extension for securing the bit therein. This method however was found to be objectionablefor a number of reasons, chiefly because of the unnecessaiziy amount of metal. required for the shank an also on ac- ;j count of the liabilit of the bit to become loosened in the she either in the course of manufacture or in use. posed, although not, so far as I am aware,

prior to my present invention, to manufac-- It has also been proture. a two-part drillby forming 'arecess in the butt-end of the bit; inserting said butt-- end intoa hole in the shank and placing said;

shank between the dies'of a drop hammer, one of which dies was provided with a projectioncorresponding in shape with the recess in the bit, whereby a portion of the metal of the shank was forced into said recess the formation'of the aforesaid depressioninthe face thereof, the inability to accurately center the bit in the shank andthe care required to properly-adjust the bit 1n the shank so that the recess in the former would .coincide in position with the cooperative projeticon on the die-plate.

.- The defects above set forth are all obviated by the method which constitutes the subject matter of the present invention and which consists in forming one or more recessesinthe bit near the butt-end thereof,' forming the shank with an excess of metal, forming in said shank a chamber to receive the butt-end of the bit, inserting said end in the shank chamber, compressing the metal of the'shank and thereby swaging the same intothe bitrecess or recesses, causing any-excessof'shank metal to flow outwardlyin the'form of afin" fins and then removing saidfin orfins. B the method there is formed a two-partdr' {the shank of which embraces the butt-endbf-thbit and has an integral rojection or projec tions swaged into and filling said recess'or re-j cesses. In the finished drill the bitisiaccuratel centered in the shank, the'h e of the shan is true and undistorted and t e outer surface or walls thereof are smoot and not disfigured by a deplression or depressions/con .iesponding with t e recess or recesses in the" it. v a

In the drawings which accompany and forma art of this specification and which I have se ected for the pur ose of more fully. disclosing my invention, igure' 1 1s aside foregoing method. Fig. 2 is a'sectional view of the bit and shank taken on the line 3-3 of";

Fig. 1' before the shank has been swaged to plate sir; Fig. 3 is a sectional view of the bit view' partly in section of a drill made by the-.1";

and shank taken? on of Fig. 1 after,v the swagi'ngoperation before the fins have been removed. Fig: 4 is a plan 1 View of thedrill after the same has been re- 1 I have'been cnt off. Fig. 5 is a plan viewof the completed drill. ,,,V

. though-f course it may be hexagona octag-' .onal crgofaany "other suitable shapev The "shainkis provided" with a chamberiB into:

Ir'i'ojv'ed from the die-plates and before thdfins' In the figures, A represents a drill-shank which isvof angular cross-section throughout its length andwhich is preferably's uare al which the bit 0, which maybe cut from a 7 ed'. The butt-end of the bit is provided with one or more recesses D which may be conlength of'steel wire ofstandard siz e, is insertvenientl formed' by means" of a grinder,

all to" the shape 01 the'shank A, but, as shown in. Fig. 2,1the' shank is slightly. largerthan the opening formed when thedie-plates are closed. To -accommodate;the'fiowgof the excess of-='met al "of {the shank, thje die-plates Ways G'G, solthatwhen the dies close-upon.

are formed: longitudinally extending:

the shank, the excess of metal of the shank When thediesfclosej on the "shank with its shank when the drill is in use. 7 has been found'thatwheh the shank is heat-.

ed to a dull cherry red, a single blow of tli I drop-hammer will suflice to form the swaged' joint between the bit and shank. After this 5 joint'has been formed, the drill is removed from the dies and the finl Lsifiwn in Fig.4 is

' cut ofi byshearing "die s or b other suitable H e fi ishe drill nieahs, thereby producing t such as shownnin- Fig: I Byproviding the WBYS'G to accommodate. 7

the flow ofthe excess" ofshankanetal when the shank is swaged to tl 1 e bit, I'am enabled to prevent the distortion of the sha e of theshank which otherwise would resu' t and to" form a shank which conforms exactly to the shape of the opening'between the die-plates.

It will be obvious that'the shape of the recess and recesses of the bit, as vwell as; the shape .of the shank, is immaterial and also that my method is not limited to the apparatus hereinbefore described, bu,t-can be carried into efiect by a variety of mechanical devices I claim; I ,As anim rovement in the art'oi making 55 two art. d ls, the method herein described Whic consists informing one or more recesses in the bit near the butt-end thereof, forming the shank with; an-eXcess of metal, forming in said shank a chamberto receive the rei cessed butt-end of the bit, inserting said end in said shank chamber, compressing v the metal of the shank and thereby swaging vthe 3 saineinto' the bit recess or recesses, causing flows outwardly into the openings formed by; T said Ways'producin'g therfins'H H.-. 35-

inserted bit, 'ajportion. of the metal. of'the' shank forced mto'the recess oi' recessfes of the bit, therebyforming a projection 01 prol: jections 'Ewhich areintegral with the'shank and which'prevent the bit from tnrning in the In'practic'e-it the excess of'sh ank metaltoflow outwardly 7 in the form of a fin-orfins and thenremoving said or fins.

In testimony whereof ,I have hereunto subscribed name this 13th day of December 

